Correct, PV 2012 has changed the sliders and their function. Contrast is still in PV 2012 but Brightness is not. It's function is now covered by Exposure wich in PV 2012 is a hybred of the old Exposure lus Brightness. However, in ACR 6.7, you can't actually get to the controls of PV 2012. Those will be in ACR 7 that ships with Photoshop CS6 (next week). ACR 6.7 added "rendering" support of PV 2012 for compatibility with Lightroom 4. ACR 6.7will need to be set to PV 2010 to make image adjustments...

Personally I think it seems to have been kind of a weird decision to include PV2012 in Camera Raw 6.7 - but not let people actually use its controls - just because the LightRoom people couldn't hold their release until Photoshop CS6 (and from what I hear Lightroom) were actually ready for release.